Astronomy Is Written For Astronomers

Not Only The Phenomena Of The Others Followed From This, But Also It So Bound Together Both The Order And Magnitude Of All The Planets And The Spheres And The Heaven Itself, That In No Single Part Could One Thing Be Altered Without Confusion Among The Other Parts And In All The Universe.

In First Place We Must Observe That The Universe Is Spherical. This Is Either Because That Figure Is The Most Perfect, As Not Being Articulated, But Whole And Complete In Itself; Or Because It Is The Most Capacious And Therefore Best Suited For That Which Is To Contain And Preserve All Things.

To Know The Mighty Works Of God, To Comprehend His Wisdom And Majesty And Power; To Appreciate, In Degree, The Wonderful Workings Of His Laws, Surely All This Must Be A Pleasing And Acceptable Mode Of Worship To The Most High, To Whom Ignorance Cannot Be More Grateful Than Knowledge.

Those Who Know That The Consensus Of Many Centuries Has Sanctioned The Conception That The Earth Remains At Rest In The Middle Of The Heavens As Its Center, Would, I Reflected, Regard It As An Insane Pronouncement If I Made The Opposite Assertion That The Earth Moves.

In The First Book I Shall Describe All The Positions Of The Spheres, Along With The Motions Which I Attribute To The Earth, So That The Book Will Contain As It Were The General Structure Of The Universe. In The Remaining Books I Relate The Motions Of The Remaining Stars, And All The Spheres, To The Mobility Of The Earth, So That It Can Be Thence Established How Far The Motions And Appearances Of The Remaining Stars And Spheres Can Be Saved, If They Are Referred To The Motions Of The Earth.